Re: A note on modern git plus ancient meld ("wrong number of arguments")

From: David Aguilar <davvid@gmail.com>
Date: Feb 10, 2012, 02:42 UTC
Message-ID: <CAJDDKr58LV9EDJZP+3S0YfyTOXFgJWD6nm=AiA19MkyBF-wb_g@mail.gmail.com>
In-Reply-To: <20120209191742.GA20703@unpythonic.net>

On Thu, Feb 9, 2012 at 11:17 AM, Jeff Epler <jepler@unpythonic.net> wrote:

Show 30 quoted lines

> I note this just in case it helps someone else track down a similar
> problem, not because I think any change needs to be made to git, as a
> version of meld new enough to not be affected by this problem is 5 years
> old.
>
> At $DAYJOB, I recently encountered a problem after upgrading from (don't
> laugh) git 1.7.1 to 1.7.8.3: one developer stated that meld failed to
> run, instead displaying the error 'Wrong number of arguments (Got 5)'.
>
> We determined that this user was running a very old version of meld
> (1.1.1) from his home directory, as opposed to the also very old system
> version of meld (1.1.5).  It turns out that the check added in
>    f61bd9c mergetools/meld: Use '--output' when available
> fails on meld 1.1.1, leading git to incorrectly believe the --output
> flag is supporrted:
>    $ meld-1.1.1 --output /dev/null --help >/dev/null 2>&1; echo $?
>    0   # i.e., detected as supported
> The test as written gives the correct ("not supported") result with meld
> 1.1.5:
>    $ meld-1.1.5 --output /dev/null --help >/dev/null 2>&1; echo $?
>    2   # i.e., detected as supported
>
> so if you encounter the message 'Wrong number of arguments (Got 5)' from
> meld, then check whether you have an ancient version of meld.  If for
> some reason you can't upgrade to at least 1.1.5, maybe you'd find the
> following configuration flags useful:
>    [merge]
>        tool = ancientmeld
>    [mergetool "ancientmeld"]
>        cmd = meld-1.1.1 \"$LOCAL\" \"$MERGED\" \"$REMOTE\"

We originally used the --output test so that we wouldn't have to check for a specific version. Does your meld support `meld --version`, and what does it output?

I'm thinking that maybe we should just try and parse the version number since it seems like we cannot depend on ancient meld's return code.

Thanks Jeff.  I'll see what we can do about it.

-- 
David